VSAN Storage Controller Cache

In “VSAN 6.0 Design and Sizing Guide” v.1.0.5, April 2015, under Storage controller cache considerations section, “VMware’s recommendation is to disable the cache on controller if possible. Virtual SAN is already caching data at the storage layer – there is no need to do this again at the controller layer. If this cannot be done due to restrictions on the staorge controller, the recommendation is to set the cache to 100% read.”.

However in “VSAN Ready Nodes”“VSAN Ready Nodes”, the storage controller in some configuration includes the cache. For example, the storage controller in the Dell PowerEdge R630.

Why includes the controller cache when VMware recommends disabing it?

It turns out the controller cache allows the larger queue depth – see this.

In “VSAN 6.0 Design and Sizing Guide”, VMware recommends the minimum queue depth is 256, and choose a controller with a much larger queue depth when possible.

For more information about the queue depth, see the following

• Disk Controller features and Queue Depth? (Yellow-Bricks)
• Why Queue Depth matters! (Yellow-Bricks)
• Queue Depth info in the VSAN HCL! (Yellow-Bricks)
• “Community” VSAN Storage Controller Queue Depth List (virtuallyGhetto)

Simple Way to Convert Time to Hours in Excel

Here is a simple way to convert the time to hours in Excel.

Hours (in decimal) = Time (in hh: mm: ss) * 24
24 is the number of hours in one day

It’s handy to caculate the file transfer rate in Excel. In the screenshot below, format column E in Number, the formula in colume E3 is C3 * 24.

Follow the simular concept, convert time to minutes in Excel

Minutes (in decimal) = Time (in hh: mm: ss) * 1440
1440 is the number of minutes in one day

Convert time to seconds in Excel

Seconds (in decimal) = Time (in hh: mm: ss) * 86400
86400 is the number of seconds in one day

Exclude Virtual Machine Hard Disk from Snapshot

A virtual machine hard disk in vSphere v.5 or v.6 can be configured in three different modes:

• Dependent: the default disk mode. The disk is included in snapshot.
• Independent – Persistent: Changes to the disk are immediately and permanently written to disk. The disk is not included in snapshot.
• Independent – Nonpersistent: Changes to the disk are discarded when power off. The disk is included in snapshot.

To change a VM hard disk to Independent – Persistent mode in vSphere v.6 Web Client:

• Power off the VM
• Delete any snapshots that currently exist
• Right-click the VM and click Edit Settings
• Under Virtual Hardware tab, expand the hard disk
• In Disk Mode, select Independent – Persistent
• Click OK

To verify a VM hard disk excluded from snapshot:

• Take a snapshot of the VM
• Right-click on the datastore storing the VM and click Browse Files
• Browse to the VM folder
• If the disk is not set to Independent – Persistent mode, a VM-00001.vmdk file is created for the disk
• If the disk is set to Independent – Persistent mode, this file will not be created

How to Save Windows 10 Lockscreen Image

1. Open Run dialog
2. Browse to %localappdata%\Packages\Microsoft.Windows.ContentDeliveryManager_cw5n1h2txyewy\LocalState\Assets
3. Copy all the files to a temporary folder
4. Rename all the files with the JPG extension by entering “ren *.* *.jpg” in command prompt

Update: 01/18/2016

An app, SpotBright, in Windows Store makes even easier to download these images.

ESXi VMkernel Port “Management traffic” Checkbox

Here is the screenshot of the services that can be enabled on an ESXi v.6 VMkernel NIC port.

All these services look very self-explanatory, until I am doing some research on the ESXi management redudancy and discovering this post.

Here is the quick summary of the post, plus others I learned about the VMkernel port.

• The “Management traffic” checkbox does nothing but enabling that VMkernel NIC for HA hearbeat traffic.
• It has nothing to deal with the management of the ESXi host. When the checkbox is not checked, you still can manage the ESXi host via vCenter Server or SSH to the ESXi host via the IP address associated with the VMkernel port.
• Why isn’t there a checkbox for iSCSI or NFS traffic?
• Answer: any VMkernel port can talk to iSCSI or NFS storage. There is no need to enable the service.
• Prior to vSphere 6, only one default gateway is defined for the ESXi host in the GUI (ESXi 5.5 allows to add additional TCP/IP stack, including default gateway & DNS, in CLI). All VMkernel ports use the same default gateway for the traffic that is not local to each VMkernel port subnet.
• Here is the sceenshot in vSphere 5.5, only one Default TCP/IP stack

• Here is the screenshot in vSphere 6, three TCP/IP stacks by default. Each can have different deffault gateway. Additional custom TCP/IP stack still needs to be created by CLI.

Hold Off Upgrading ESXi 5.5 with VSAN to ESXi 6.0

If you are running ESXi 5.5 with VSAN, DO NOT upgrade the ESXi host from 5.5 to 6.0. When mixing ESXi 5.5 and 6.0 in the VSAN cluster during the host upgrade, it can cause permanent data loss. See this VMware KB2139969 for more information. As December 25, 2015, no fix is available yet.

If you have to upgrade to ESXi 6.0 now, the safe approach is to migrate the VMs on the VSAN to other non-VSAN storage prior to the upgrade.

Windows Server Message Block (SMB) Protocol

Versions

There are several different versions of SMB used by Windows operating systems:

SMB Version	Operating System	Note
CIFS	Windows NT	superseded by SMB1
SMB 1.0 (or SMB1)	Windows 2000, XP, Server 2003, Server 2003 R2
SMB 2.0 (or SMB2)	Windows Vista (SP1 or later), Server 2008
SMB 2.1 (or SMB2.1)	Windows 7, Server 2008 R2
SMB 3.0 (or SMB3)	Windows 8, Server 2012
SMB 3.02 (or SMB3)	Windows 8.1, Server 2012 R2	In Windows 8.1 and Server 2012 R2, the option to completely disable CIFS/SMB1 support is introduced. It is not the default configuration.
SMB 3.1.1	Widnows 10, Server 2016

Negotiated Versions

Here’s a table to help you understand what version you will end up using, depending on what Windows version is running as the SMB client and what version of Windows is running as the SMB server:

OS	Windows 8.1 WS 2012 R2	Windows 8 WS 2012	Windows 7 WS 2008 R2	Windows Vista WS 2008	Previous Version
Windows 8.1 WS 2012 R2	SMB 3.02	SMB 3.0	SMB 2.1	SMB 2.0	SMB 1.0
Windows 8 WS 2012	SMB 3.0	SMB 3.0	SMB 2.1	SMB 2.0	SMB 1.0
Windows 7 WS 2008 R2	SMB 2.1	SMB 2.1	SMB 2.1	SMB 2.0	SMB 1.0
Windows Vista WS 2008	SMB 2.0	SMB 2.0	SMB 2.0	SMB 2.0	SMB 1.0
Previous Version	SMB 1.0	SMB 1.0	SMB 1.0	SMB 1.0	SMB 1.0

* WS = Windows Server

Check SMB Version

In Windows 8 or Windows Server 2012 or later, a new PowerShell cmdlet can easily tell what version of SMB the client has negotiated with the File Server. For Windows version prior to Windows 8, there is not an easy way – need to use Network Monitor, Message Analyzer (recommended) or Wireshark to capture and look into the packets.

To check the negotiated SMB version between the client and file server

1. Access a remote file server (or create a new mapping to it)
2. Use Get-SmbConnection

To check the SMB version on the local computer

1. dir \\localhost\c$
2. Get-SmbConnection –ServerName localhost
   • run the Get-SmbConnection cmdlet within 10 seconds after the dir command
   • the SMB client will tear down the connctions if there is no activity

Recommendation

Microsoft strongly encourage to update to the latest of SMB. However, be aware of compatibility with the older Windows operating systems and third-party application implementation.

• VMware
  • vCenter Server Appliance 5.5.x / 6.0.x and vRealize Automation 6.2.x support SMB1 only (KB2134063)

Source

Microsoft Jose Barroeto’s Blog

• Windows Server 2012 R2
• Windows Server 2016